Apparatus for producing automobile frame side rails and analogous devices



July 30, 1935. H. F. KULAS ET A1.

APPARATUS FOR PRODUCING AUTOMOBILE FRAMESIDE RAILS AND ANALOGOUS DEVICESFiled April 14, 19.52

B Y 'Jh/155 H. C/Po we mvo /PuaoLPH H. Tvc/v5 A T T ORNE Y XM ALMPatented July 30, 1935 FRAME SIDE RAILS AND DEVICES ANALOGQUS Howard F.Kulas, James H. Crowe, and Rudolph H. Thorns, Midland Steel ProduLakewood, Ohio, assignors to The cts Company, Cleveland,

Ohio, a corporation of Ohio Application April 14, 1932, Serial No.605,210 Y 6 Claims.

This invention relates to new and useful im.- provernents in apparatusfor producing automobile frame side rails and analogous devices.

An important object of the inventionis to L; provide apparatus forproducing channel-shaped automobile frame side rails which possesscomparatively high elastic limits and percentages of elongation andwhich do not require the expensive and laborious straightening incidentto heat treatment.

Another important object of the invention is to provide means forcooling the rails while they are held confined against movement to preclude distortion or deflection.

A further object of the invention is to provide apparatus in which thenormal structure of steel possessing comparatively high elastic limitsis maintained throughout the operation thereon and in the finishedproduct and is not left in the unstable and temperamental state which isa necessary incident and condition existing in heat treated rails.Moreover, with the apparatus the rails are formed hot and there is nodanger of plastic distortion of rails at the juncture of the web andanges thereof such as will occur in some grades of steel when the siderails are formed cold.

Other objects and advantages of the vinvention will become apparentduring the course of the following description.

In the accompanying drawing forming a part of the description andwherein like numerals are employed to designate like parts throughoutthe several views,

Fig. 1 is a top plan of the bed of a punch press illustrating theimprovements applied thereto,

Fig. 2 is a side elevation of a portion of the improved punch,

Fig. 3 is a similar view of the opposite end of the punch, Fig. 4 is avertical transverse section of the bedplate and punch showing theposition of the parts when the punch is lowered into the die during theforming operation, and,

Fig. 5 is a similar view illustrating the punch in elevated position forremoval of the work.

In the past few years a very definite demand has arisen for light gaugeheat-treated automobile frames, especially those used `in modern heavytrucks and busses. The side rails of such frames range from twenty toforty or more feet in length and are of the usual channel shape crosssection. Heat treatment of these rails boosts the elastic limit thereofbut has the effect of loweringthe percentage of elongation. However,this heat'treatment Yof the exceedingly lor-ig side rails has a veryserious drawback from'the standpoint of manufacture since it causes orpromotes all manner and form of bending,warp` ing, twisting anddistortion inV the r'ails,'-re quiring difficult and costly processes ofstraightening, after heat treatment and sand blasting. Under thispractice as disclosed'in an Varticle entitled Treats Alloy Steel SideFrames in the July 1930 issue of Steel it is the custom to work Y withlowcarbon steel plates not exceeding a percentage of 0.30 carbon so thatthe plates can be cold formed to the requisite shape and chan nel'crosssection without danger of being weakened by cracking. As stated in thispublication', the plates are first annealed in a fortyffoot,foi1v fired,car type furnace, equipped withfautomatic pyrometer control. In thisfurnace the plates are brought up gradually over a period of 18 hours toa temperature of 1550"4 F. and are then :held at that temperature for 8hours more After they are cooled down in the furnace to 600 F., they aretaken out and cooledin the air to room temperature. Obviously, this merestep of 1an--y nealing the plates consumes a great amount of time and isonly the initial step in a long and tedious method. c l' After theplates have cooled down to room temperature, they are formed cold vintochanneled rails after which theyY are heated up to 1550"F. in the heattreating furnace `and quenchedby plunging upv and down whileunrestrained against distortion in an oil bath atabout F.- There-.-after the rails are'drawn at a temperature ranging from 900 F. to 1100F. depending upon the carbon and alloy content ofthe steel. After thedraw, the rails are air-cooled and sand-blasted and in their warped,twisted and deformed condition must be subjected to a dinicult processof straightening to render them usable. This straightening of a singleside rail after the heat treatment and draw requires the services.v offour men for approximately one hour on a special straighteningmachineand in order to make this method a commercial production job, abattery of these special straightening machines is a. necessity.

In order to reduce the time and expense "required in the annealing, heattreatment vand straightening operations and vat the same vtime producerails having as high or higher elastic limits and percentages ofelongation as those produced by older processes, it has been'disfcovered that all of this can be accomplished by the use of differentsteel and by a different meth'.-

od of manufacture. In carrying out this new method, any of a number ofdifferent kinds of steel may be employed, depending upon what elasticlimits and percentage of elongation are desired. By way of example, itmay be stated, that it has been found that by following the hereindisclosed method of manufacture, that S.A.E. 1360 steel containingCarbon .55 .70 Phosphorus .040 Manganese .90 -1.20 Sulphur .050

will yield a minimum elastic limit of approximately 75,000 pounds persquare inch and elongation of 25 percent.

Steel of the following formula:

Carbon .45- .50 Chromium .40- .65 Manganese 1.1 1.4 Silicon .65- .90

will yield a minimum elastic limit of 90,000 pounds per square inch anda 25 percent elongation, while steel of this formula:

Carbon .55- .65 Chromium .40- .65 Manganese 1.1 1.4 Silicon .65- .90

will give a minimum elastic limit of 100,000 pounds per square inch anda 20 percent elongation.

Under the present preferred method, steel of the above formulae or thatwhich possesses generally similar characteristics is put into therequisite shape to produce the desired shape of side rails and is heateduniformly to a substantially low red heat, well below its lower criticalrange. While the degree of heating is somewhat dependent upon thestructure of steel used, it is preferable that it be heated only to aheat by which it can be readily formed without any appreciable scalingwhen formed and under which the micro-structure'of the steel is notdisturbed nor internal strains set up, but in which the pearliticcondition is maintained. In other words, the' structure of the steel ispreferably maintained in a normal state and is not put into an abnormalor unstable state such as exists when the steel is subjected to anactual heat treatment and because of such heat treatment, might in someof its proposed uses lose some of its desirable characteristics byfriction or by static or dynamic stresses. By not heating the steelvbeyond its transformation stage, better control during forming isattained and the steel after formation still retains its normal state.

While the foregoing manner of heating the blanks is perhaps bettersuited to the present day production equipment from many standpoints, itis possible that the herein disclosed method can be carried out byactually heat treating the blanks in a different manner from what hasbeen proposed heretofore in order to prevent distortion of the rails andobviate the necessity of a subsequent straightening operation. In suchevent, the blanks may be heated up to a temperature of 1550 F. or theparticular transformation temperature of the particular steel employedto be] quenched with a coolant in a press as will be presentlydescribed. Of course, when itis proposed to elevate the temperature ofthe steel 'above its transformation stage, lower percentages of carbonand variations of the other constituents lto bend it into the' die intochannel shape with parallel spaced flanges. The punch is left in itslowered position firmly holding the rail in the die. According to oneplan the rail is not immediately removed from the press after itsformation nor is the punch elevated from the die as would be the naturalexpectation, but the punchis retained in its lowered position holdingthe blank against any possible movement between the die and punch whilea coolant circulated in and about the press in a manner to be presentlydescribed, conducts heat away from the confined rail and associatedpress parts in a thoroughly uniform manner. The punch, die andassociated bulky press parts also of themselves cooperate to some degreeto the dissipation of heat in the rail. With the rail so held andrestrained against any possible movement during cooling, there is noopportunity for it to warp, bend, curl or distort and it is so retaineduntil it has cooled suliciently to be safely handled without thepossibility of the web and flanges losing their shape by warping orbending. The cooling of the blank may be hastened by circulating acoolant through the die, punch and associated parts or provision may bemade for flowing a coolant in direct contact with the flanges of therail while it is held between the punch and die or suspended by thepunchwhen the latter is raised. In cases where the blanks are heatedabove their transformation stage, this later method of cooling orquenching is employed.

While the cooling of the restrained or confined side rails may beaccomplished in several different ways, within or without the press andmay either be by conduction, convection or both, the accompanyingdrawing illustrates one economical and commercially productive way ofrapidly dissipating the heat without adverse effects upon the rails.

Referring now to the accompanying drawing for details, the numeral Idesignates a bed of a press having spaced parallel side rails 2 defininga space between them for the reception of dies 3 and 4 between which avertically reciprocable ejector 5 operates for ejecting the work afterbeing formed. Beneath this ejector, the bed plate is provided with aplurality of drain openings or passages 5 which may have suitablestraining means associated therewith to prevent clogging of the holeswith scale and other deleterious material.

Due to the length and shape of the side rails, the dies 3 and 4 are madeup of a plurality of sections as clearly shown in Fig. l. 'Each of thesedie sections in proximity to a portion of the rail formed thereby isprovided with a longitudinally extending passage 1 terminating at oneend in an inlet port 8 and at its opposite end with an exhaust port 9. Apipe or conduit l0 extends longitudinally alongside of the bedplaterails 2 at each side of the press for the conduct of a coolant of `anysuitable character to the two sets of dies and 4. A branch pipe H fromthe conduit il) leads to its respective inlet port 8 in the die forconveying coolant thereto. As the coolant passes along the side of thedie, it absorbs heat from the die and article being formed in the Pressafter which the coolant passes out of fio y cach die section through abranch pipe 1I=2which vis'fconnected.with an' outlet pipe yI3 extending.alonggeach-side of the press to apoint of vdischarge orzreturn tothesource toners-cooled and circulated again through the dies. Ifdesired, the ejector 5 may also be provided.r with .suitable rairorliquid coolantpassag'eslw.- i

The punchior male'die of the press indicated by the numeral It and whichis adapted to ter the female die `toiorm the sidev raiL'isalso sectionalin character, reach section being coredrout'adjacent itsrside Walls to.provide apair of longitudinally extending coolant passages or com--partments. I5 and'fIG. Each passage atvone end. adjacentlthebottom'itl'iereof is provided with an inlet port' Illa'nd at-..i`tsopposite end adjacent the top thereof with an outlet port I8. A supplypipe I9 for the coolant extends longitudinally of the punch and isconnected to a source of supply by a flexible conduit which permits theusual movements of the punch. The pipe I9 is connected to the inlet portof various punch sections by branch pipes ZI to constantly supply thecoolant to the individual punch sections. This coolant after becomingwarmed circulates out of the passages I5 and I6 through the exhaustports I8, branch pipes 22 which in turn are connected to a commonexhaust pipe 23, which like the supply pipe at its end, is provided witha flexible conduit 24 to permit movements of the punch.

Coolant pipes 25 extend along both sides of the punch longitudinallythereof and are suspended therefrom by means of the brackets 26. Thesepipes 25 are provided with a series of apertures permitting the coolantto be sprayed down upon the dies, punch and the formed rails 21 to morerapidly cool them. These spray pipes 25 are connected to the coolantsupply pipes I9 by means of valved couplings 23 so that the use of thespray pipes may be optional and the supply of coolant thereto controlledby the valve coupling 28. It is of course obvious that the branch pipesI I and I2 may be connected with the die sections 3 and 4 by quickdetachable couplings to facilitate change of dies When desired and thesepipes may be readily disconnected from the rails of the bedplate.Likewise, suitable detachable connections may be provided fordisconnecting the coolant circulating pipes from the punch sections.

From the foregoing description, it will be obvious that a blank, heatedas above described is suitably centered upon the dies at which time thepress is operated to cause the punch I4 to descend upon the blank andform it into channelshape shown in Fig. 4. As stated hereinbefore, incases where the blanks have been given only a low forming heat, 'thepunch is not elevated immediately after the formation of the rail but ispreferably permitted to remain in the position shown in Fig. 4 topreclude any possible movement of the rail while it is so clamped andbeing cooled. The cooling of the rails may be hastened by circulatingcoolant through the die and punch passages or by spraying the coolantfrom pipes 25 directly upon the rail, punch and dies or upon the rail onthe punch when elevated as shown in Fig. 5. This latter form of coolingis preferably resorted to when the blanks are heated abovethetransformation stage as it takes the place of the quench under theheat treatment plan. After the rail has been cooled to the extent thatthere is no possibility of bending, warping or distortion whenrestraining action thereon is released, the press is operated to elevatethe punch I4 and ejector 5 to eject the formed rail from the die.

:tween the dies. was-heated prior to forming, .there is no'tendencydirectly into contact With the side railk and fmale .die to more`rapidly cool the same to handling temperatures. :When the rail is beingformed =betweenithe dies a'sfsliown in Fig. 4;*'it will be `apparentthat the-upper edges of thef fiang'esof the rail are exposed between themale andv female diesso thatcoolant `from pipes 25 may be sprayeddirectly into contactwithi the flangeswhllefthe entire-rail is firmlyheldin formed position ibe- Due to the fact that theblank for the railto crack or become ruptured at points where the flanges of the rail arebent from the fiat blank, such as is apt to occur in certain grades ofsteel formed cold. Moreover, it is preferred that, the blanks to be onlyheated within a certain range which takes into consideration the idea ofminimizing the amount of scale formed on the side rail and themaintenance of the steel structure in its normal condition.

Obviously, the herein disclosed apparatus and method not only makes itpossible to obtain greater elastic limits with certain increasedpercentage of elongation in side rails which must be given channel shapeformation, but also reduces the time incident to and the many tedioussteps involved in the usual heat treatment and straightening process.Moreover, this increase in elastic limit has a tendency to increase theductility of the steel and prevent the rail from taking on a permanentdeflection or set under load, but is controlled by the component partsor structure of the steel within a range so as not to adversely affectthe tensile strength of the material or its resistance to static anddynamic stresses under the proposed uses. Last, but not least, is thetremendous saving in equipment and the decrease of time required for theproduction of side rails resulting from practicing the herein disclosedmethod as compared with the laborious heat treatment and straighteningprocess.

It is to be understood that the herein described apparatus is notlimited to the production of side rails as the other component parts ofthe frame and analogous devices may be similarly formed and that variouschanges in the sequence of steps,

components of the steel and their proportional metal while held againstmovement between said members, and common supply and exhaust means forcirculating coolant through the plurality of sections.

2. The combination with a metal Working press including male and femaledie members imparting channel form to heated metal pressed therebetweenwith the edges of the flanges exposed, and means for discharging coolantdirectly upon the formed flanges of the channel while held by the diemember.

3. The combination with a metal working press including a verticallyreciprocable punch for imparting channel form to heated metal, ofcoolant spraying means arranged on opposite sides of the punch andmovable therewith for spraying coolant -directly upon the formed flangesof the channel While held by the punch.

4.. The combination with a metal working press including a female diehaving liquid drain openings, a vertically reciprocable punch adapted toenter the die for imparting form to heated metal, of coolant dischargingmeans movable with the punch for discharging coolant directly upon thepunch, die and formed metal.

5. The combination with a metal working press including male and femaledies for forming heated metal into a anged article with the flangesexposed between the dies when the latter are in cooperative formingposition, and coolant spraying means disposed to spray coolant upon theexposed iianges of the article while it is held clamped between thedies.

6. The combination with a metal working press including male and femaledies for forming heated metal into a flanged article, cooling means forcausing the article to contract and adhere to the male die as it iselevated, and coolant spraying means carried by the press in position toAspray coolant upon the article held elevated by the male die.

HOWARD F. KULAS. JAMES H. CROWE. RUDOLPH H. THOMS.

